This paper reports an anomaly in the yield strength of dislocation
interacting with stacking fault tetrahedra (SFT) in Cu, reveals atomic
mechanisms that are responsible for the anomaly, and further shows the
thermodynamic driving force for the atomic mechanisms to prevail.
Instead of monotonically increasing with the area of intersection cross-
section, the yield strength first increases and then decreases with the
area. The decrease, or the anomaly, is due to a change of atomic
mechanism of the interactions-the SFT goes through a morphological
transformation. The thermodynamic driving force for the transformation
derives from the competition between the elastic energy of dislocations
and the stacking fault energy. DOI: 10.1115/1.4005266